Building a home for the NOvA near detector

As part of the outfitting of the NOvA Near-Detector Cavern, Byus Steel and Area Erectors recently installed steel platforms, stairs and ceilings. The companies are subcontractors to Kiewit Infrastructure Co. Photo: Cindy Arnold

This week contractors reached the final phase of the NOvA Near-Detector Cavern construction project—on time and without any accidents or injuries.

Design of the cavern started in 2008, with the help of engineering firms MWH and Hanson Professional Services. Crews from Kiewit Infrastructure Co. have been working on building the near-detector cavern since May 2012.

"As a laboratory we're just thrilled with their work," said FESS engineer Russ Alber. "Rock excavation is dangerous and unpredictable. Kiewit's proactive approach to safety has been key to keeping the job safe."

The crews prepared the site by relocating utility pipes and cables in the NuMI beamline to make way for construction. Kiewit excavated nearly 2,000 cubic yards of rock to create the cavern. They've completed the installation of the steel platforms and drip ceilings, which will provide protection to and access around the future NOvA near detector. The effort has taken 26,000 man-hours so far.

In the last phase of the project, Kiewit crews will outfit the new cavern with electrical, mechanical and safety systems. In May they are scheduled to turn the completed facility over to the laboratory, which will then get to work installing NOvA's near detector.

—Kathryn Jepsen

In Brief

Young scientists meetwith deputy director on Friday to prepare for Snowmass

This Friday, early-career scientists will meet with Fermilab Deputy Director Young-Kee Kim in preparation for this summer's Snowmass conference in Minnesota. All early-career scientists at Fermilab are welcome to attend.

The meeting is held by the Snowmass Young Physicists Movement, an effort by early-career physicists to contribute to the long-range plans of the field of particle physics, which are formally charted by the U.S. particle physics community at the Snowmass conference. YPM is a channel through which undergraduates, graduate students, postdocs and untenured scientists can help shape future particle physics experiments.

At Friday's meeting, which begins at 5:30 p.m. in the Users' Center Music Room, scientists will meet with Kim and Snowmass conveners to collect input for a survey intended to take the pulse of the up-and-coming generation of particle physicists.

The plan is to distribute the survey to scientists working at the various frontiers of particle physics. Results will be presented at the Snowmass meeting.

If you'd like to attend Friday's meeting, please notify Bjoern Penning at penning@fnal.gov.

Photos of the Day

Glimpsing the lives of coyotes

Wading in the water of Lake Law, a curious coyote peers from behind the dried reeds. Photo: Steve Krave, TD

A coyote casually strolling on the ice of Dusaf Pond appears to follow the direction of the traffic sign. Photo: O'Sheg Oshinowo, PPD

Stand back! Lori Limberg, BSS, took this picture while safely inside the building at Site 52.

In the News

Neutrino observatory site work to kick off in February [in India]

From The Hindu, Jan. 21, 2013

Site work for the Rs.1,350-crore India-based Neutrino Observatory (INO) project, which is coming up along the West Bodi Hills in Theni district, is set to begin in February.

The ambitious underground experimental laboratory, being set up with multi-institute collaboration, has obtained all clearances and got possession of the land from State Government, both for the observatory in Pottipuram village and the project headquarters/research and development centre in Madurai. Expected to be completed in four to five years, the INO will house a massive 50,000-tonne magnetic detector to study elusive neutrinos, which are an interesting area in particle physics.

Shedding light on the Higgs

The Higgs boson does not directly interact with photons, but creates pairs of them through loops of other particles—perhaps including particles that have yet to be observed.

In the Standard Model, the Higgs boson interacts with other particles in proportion to their mass, yet its decay into pairs of massless photons is one of the most interesting and important channels to study. Not only was this one of the main discovery channels for the Higgs boson candidate observed last July, but it may also be the key to understanding if this new particle fits into the Standard Model or is the first glimpse of new physics. A recent result from DZero contributes to the ongoing efforts to determine the nature of this newly observed boson.

Because photons are massless, the only way for a Higgs boson to decay into a pair of them is through an intermediate "virtual" loop of massive particles, like top quarks (see graphic). Particles that exist but have yet to be discovered could affect the decay rate, giving physicists an opportunity to probe for new physics. Some new models of physics predict a version of the Higgs boson that disfavors its decay into quarks and leptons,
and enhances its decay rate into photons.

To optimize their sensitivity, DZero analyzers classified events based on the quality of the observed photons and created samples with different background compositions. An event classifier was developed for each sample, using ten different variables that characterize the event to separate Higgs boson events from the background.

The improved techniques used in this analysis led to a 40 percent gain in sensitivity over the previous result from DZero. No significant excess of events was observed, as expected in this case since this single channel is only marginally sensitive to the Standard Model Higgs boson. The analyzers also tested the model where the Higgs disfavors decaying to quarks and leptons, excluding the mass range 100-113 GeV. Because it encodes important information about the interactions the Higgs boson has with other particles, this improved analysis will make important contributions to the combined Higgs boson results from DZero and the Tevatron.

—Mike Cooke

These physicists made major contributions to this analysis.

After Tevatron operations concluded, the DZero detector was reconfigured into an exhibition area. The exhibition area coordinators oversee the efforts to share this piece of particle physics history and present fun and educational tours to the public.